Cracking still and process



Nov. 8, 1932. w. 1 BAGWILL CRACKING STILL AND PROCESS Filed May 9, 1928 v2` Sheets-Sheet 1 .Stek E Nov. 8, 1932. w. L. BAGWILL CRAGKING STILL AND PROCESS Filed May 9, 1928 Sheets-Sheet 2 Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE CRACKING STILL AND PROCESS Application filed May 9, 1928.

My invention is a cracking still for cracking oils and the process of operation thereof.

An object of my invention is a cracking still suitable for cracking what may be termed fuel oils containing a. relatively large proportion of asphalt; and in which the heavy residual products are treated by a cracking process, thereby separating the light oils from the asphalt like substances.

Another object of my invention is a cracking still in which the oil passes through a first pre-heater then through a vapor heat interchanger, then through a second preheater and a temperature booster', being passed into the bottom of the still. The vapors in the still are subjected to a high temperature through the medium of flue gas pipes passing at different levels through the still, the hot gases entering the top, the cooler gases discharging adjacent the bottom, these gases flowing through flues. The tar and asphaltic like substances flow into a tar pot at the bottom of the still where they are subjected to the action of super-heated steam, this causing a cracking of these products, the vapors rising` and bein g treated in the upper part of the still.

.A further object of my invention is the collection of carbon and condensed vapors in the vapor heat interchanger, these being returned to the tar pot. l .another object of my invention is the use of a solution of rubber distilled with the oil, the fumes of the rubber vapor acting to detach carbon from the flue pipes, to cutdeposits of the cracked oil in the oil pipes, and to keep the liquid .in the tar pot from forming carbon on the steam pipes. The rubber fumes also neutralize the sulphur fumes in the cracked oil, thus protecting the pipes and making a better gasoline product.

A feature of my invention is the construction of a still which is materially narrower than its height, and preferably has single flues. spaced at equal distances from the side Walls on the center vertical line of the still.

Another feature of my invention is an eX- pansive joint for the fines located outside of the heads of the still, these expansion joints having a pair of flanges connected to a sleeve Serial No. 276,394.

and an inner pipe fitting in the sleeve, the flanges being connected by a ring like pipe having a split on the inside surface, the ring being welded to the flanges at this split.

My invention in the structural characteristics involves some of the features of my Patent No. 1,560,891, for a cracking still for mineral oils, dated November 10, 1925.

My invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a longitudinal section through the still taken substantially on the line 1 1 of Fig. 2 with certain of the parts illustrated in diagram to show their construction and to indicate the manner of operation,

Fig. 2 is a vertical section on the line 2 2 of Fig. 1 in the direction of the arrows,

4ig. 3 is a vertical section on the line 3 3 of Fig. 1 in the direction of the arrows,

Fig. 4 is an enlarged longitudinal section 70 through one of the expansion joints, as shown at 49 in Fig. 1.

Referring first to Fig. 1 a first oil preheater l1 has an intake oil pipe 12 and an outfiow oil pipe 13, the oil following the line of the arrows lil, 15 and 16. I find my still efficient for treating an oil designed as fuel oil having a specific gravity of substantially 18O Baume and having an asphaltic content of substantially 30%. The 80 oil flows into a vapor heat exchanger 17 passing downwardly through a pipe coil 18 therein and being discharged through the pipe 19. This pipe connects to a second oil pre-heater 20, the oil discharging through the pipe 21 following the direction of the arrow 22 to the temperature booster 23 in which the oil passes through a coil of pipes 24. This temperature booster is heated as hereunder set forth and raises the temperature of the oil to substantially 5500 or 600o F. The oil is discharged from the booster through the pipe 25 and enters the valve pipe 26.

The structure of the still proper, designated generally bythe numeral 27, is substantially as follows, having reference to Figs. 1, 2 and 3 t The shell of the still has side Walls 28, a bottom plate 29, top 30, With end heads 31 and 32. An oil and vapor dome 33 is connected to the top of the still, there being an 1 sidered as somewhat oval, being` slightlyk larger across the top than adjacent the bottom. Inside the still there are y'three gas Hues 36 which extend through the heads. rIhe upper pipe is connected by a connecting Hue 37 to the furnace 38. The upper and the center fluesare Vconnected outside of the still by the return bend pipe 39, and the center and the lower Hues are connected by the return bend pipe 40. `These three Hues in the still are spaced at equal distances from the sides yof the still and in` vertical alignment. l

The gases after leaving the lowermost Hue pass through a heater pipe 41 in the second oil pre-heater and then are subject to the action of a power fan 42. This power fan blows the gases through a second heating Hue 43in the Hrst oil pre-heater 11. I find `the operation ,satisfactory with the gas entering the rupper Hue from the furnace at substantially a temperature of 1600 F. and leaving the lower Hue with a temperature of 800 F., the temperature of the Vgas after fleaving the first oil pre-heater 11 being substanti ally 300 F.

The tar pot 35 is provided with steam injection pipes 44, the steam being blown in under pressure through steam pipes45. I find it satisfactory to have the steam at a temperature of about 900 F. The oil fills the still to about half way between the bottoin plate 29 and the lower surface of the lowermost Hue'. The residual and heavy products of the oil with most of the asphaltic body Hows into the tar pot where it is subjected to the action of the superheated steam, the residual, heavy asphaltic material being discharged through the discharge pipe 46.

Connected to the dome there is an oil vapor pipe 47 which discharges at the upper portion' of the vapor heat exchanger 17 and discharges therefrom through the pipe 48, being then led to refining towers or the like. There is a blowout valve 48 in the lower part of the vapo;` heat exchanger.

' The construction' of the expansion joint designated generally by the numeral 49 is illustrated particularly in Figs. 1 and 4. `In this construction a sleeve 50 is welded or otherwise secured to the heads 31 and 32, fitting suitableopenings, and has an upwardlyHared flange 51. The Hue 36 may be con- 3 sidered as havingan extension 52 which lits inside the sleeve, thus passing beyond the heads 31 and 32, this extension having an annular Hange 53.

These Hanges at the outer end may be spaced apart if desired, or the edges may contact; and around these` edges there is a ring 54 formed of a pipewith a split. 55 on the inner surface. This split engages the outer edges of the Hanges 51 and 53 and is welded thereto.

.The Hues 36 in the still are preferably metal tubes unlined. The Hue 37 from the furnace is preferably a lined tube and has a snug Ht inside of the extension 52 of the Hues 36, being sealed in place in the usual manner. The return bends 39 and 40 are also preferably lined tubes to prevent radiation of heat and fitinside of the extension 52 ofthe Hues 36. By this construction it will be seen that as the Hues 36 expand and contract due to changes of temperature, that the Hanges 51 and 53 may bend slightly; and also the pipe 54 may expand and contract due to the action of the Hanges thereon, thus giving an eHicient expansion joint.

The temperature booster 23 is heated by hot gases passing inwardly through the pipe 56 and outwardly through the pipe 57, this leading through a tunnel to the stack. It is also `to be understood that the Hue gases from the Hrst oil pre-heater are discharged to a suitable stack. l

VThere is a gooseneck construction 58 connected to the base of the vapor heat exchanger 17, this having a pipe 59 leading to the tar pot 35. There is a closure valve 60 in the gooseneck. It is also to be understood that the various pipes are provided with valves wherever necessary.

In preparing the rubber solution I utilize old rubber, suoli as old automobile tires or the like, which is boiled in oil at about 400 F. until all the rubber is dissolved from the fabric of the tires or other structure. This is boiled with fairly enough oil to melt down the rubber, making ak heavy solution. In the crude oil which is being distilled I use substantially 4 oZs. of the rubber solution per bbl. of crude oil.

TheA action of the rubber and of the fumes of the rubber as they are distilled appears to be to detach the carbon from the Hue pipes and to alsol cut the deposit of cracked oil which sometimes forms in the oil pipes, and also to keep the liquid in the tar pot from forming carbon on the steam pipe. The rubber solution appears to work as well in the liquid oil as in the vapors. The fumes of the rubber also neutralize the sulphur fumes in the cracked oil and thus functions to protect the pipes from these fumes and to facilitate the making of a better gasoline product.

The manner of operation and functioning of my still is substantially as follows, it being understood that I may vary the pressure in Civ LSU

the still; and in practice I vary the pressure from atmospheric to substantially three pounds per square inch. The crude oil first enters the lirst oil pre-heater where it is subjected to the action of the ilue gases after they have heated the still and the second oil pre-heater. The oil then travels to the vapor heat exchanger 17 where it is subjected to the temperature of the hot vapors direct from the still. The oil then passes to the second oil pre-heater where it is subjected to the action of the iue gases immediately after leaving the still, and from the second pre-heater the oil passes to the temperature booster where it is heated by hot gases derived in any suitable manner. The oil then enters the bottom of the still and preferably does not lill the still to such an extent as to contact with the flue pipes.

In the operation of distilling, the vapors of the oil pass upwardly into the dome and outwardly through the pipe 47 through the vapor heat exchanger and then to appliances for further treating the vapors. At the bottom of the still the asphalt like products flow into the tar pot and are subjected to the action of superheated steam. This action tends to vaporize any of the vapors contained in the residual oil, these vapors then passing upwardly through the still.

The products from the oil pot may be drained out through the pipe 46. In this operation the condensed 'oil vapors and any carbon deposited in the vapor hea-t exchanger 17 iiows by means of the pipe 59 to the tar pot and is again subjected to a distilling action. The rubber 'solution being mixed in with the cil causes an action in all of the parts distilled and connections to remove carbon deposits and neutralize the sulphur etc.

Various changes may be made in the principles of my invention without departing from the spirit thereof, as set forth in the description, drawings and claims.

I claim:

l. A still comprising in combination a tank like structure having heating flues therein, means to flow oil into the bottom of the structure below the flues and out of conta-ct therewith, means to draw oil vapors from the top of the structure, a receptacle forming a tar pot connected to the base of the structure and openly communicating with such structure, steam pipes entering said receptacle to vaporize the oil, and means to draw residual oil from the receptacle.

2. A still comprising a tank structure having means to flow oil into the bottom and with an outlet for oil vapors at the top, heating iues in the structure above the oil and out of contact therewith, a receptacle forming a tar pot connected to the base of the tank and openly communicating with such tank and having means to heat the oil therein for vaporization, and means to flow residual oil out of the receptacle.

3. A still for cracking oil having in combination a shell forming a still body of substantially ovate cross section with flat sides from the sides one above the other with return connections at the ends of the shell, an infeed connection for oil at the base ot' the shell, a receptacle forming a tar pot formed at the base, an outlet for oil vapors at the top, means to heat the oil in the said receptacle to vaporize such oil, and means to iow the residual oil out of said receptacle.

4. A still for cracking oil, having in combination a. shell forming a still body of substantially ovate cross section, with flat sides and the apex at the bottom, continuous combustion passages extending' through the body from end to end, means to flow oil along the bottom of the shell, out of contact with the lues, means to take olf vapors from the top of the shell, a receptacle forming a tar pot connected to the base of the shell to receive the residual oil, means to heat the receptacle for vaporization of the oil, and means to draw oit the residual oil from the said receptacle.

5. A still :tor cracking oil as claimed in claim 4, means to collect condensed heavy vapors of part of the oil from the takeoff, and

means to return such condensed heavy vapors to the receptacle.

6. A method of cracking oil, comprising flowing hot liquid oil into the bottom of a still, such still being heated by passing hot gases through heating fiues in the still, the said iues being out of contact with the liquid oil, running the residual oil into a receptacle in the base of the still, heating the oil in such receptacle, withdrawing the oil vapors at the top of the still and drawing oli the residual oil from the said receptacle.

In testimony whereof I have signed my name to this specification.

WILLIAM L. BAGWILL. 

